U.S. Pat. No. 5,022,872 discloses a jack, as shown in FIG. 8. The jack comprises a housing 5, a first contact 6, a second contact 7 and a third contact 8. The first contact 6 has a spring contact portion 65 extending upwardly and inwardly from one side of a rectangular frame 64 and is mounted in a groove 109. The first contact 6 also has a soldering tail 66 extending downward from a lower edge of the frame 64. The second contact 7 has the same configuration as the first contact 6. The third contact 8 is formed as a U-shaped metal piece and has two flexible contact pieces 88 extending forwardly from a top and bottom edges thereof for gripping a tip electrode of a plug (not shown) therebetween. A pair of soldering tails 87 respectively extend downward from opposite sides of the third contact 8.
The spring contact portions of the first and second contacts 6, 7 and the contact pieces 88 of the third contact 8 are bent to possess a certain degree of resiliency for securely abutting the plug. However, due to a large required contact normal force from the spring contact portions and the contact pieces against the plug, the contact portions tend to yield or become damaged after a period of use, resulting in an unreliable connection with the plug.
The present invention is directed to solving the above problems and features an audio jack having an element providing a controlled normal force in addition to signal contacts for retaining a mating plug, thereby effectively preventing the signal contacts from mechanically failing.
A main object of the present invention is to provide an audio jack with a controlled normal force for retaining a mating plug.
Another object of the present invention is to provide an audio jack which effectively prevents contacts from mechanically failing.
An audio jack in accordance with the present invention comprises an insulating housing, a plurality of resilient contacts, a plurality of fixed contacts and a retention pad securely fixed in the housing. The housing defines a longitudinal plug-insertion hole therethrough for receiving a mating plug.
Each resilient contact includes a fixing section for fixing the resilient contact in the housing and a cantilevered beam diagonally extending opposite to the fixing section. The cantilevered beam extends into the plug-insertion hole from a top wall of the housing. A contact section is formed at a distal end of the cantilevered beam for contacting the plug. Each fixed contact is configured like the fixing section of the resilient contacts. The retention pad includes a base retained in the housing and a protrusion for pressing against the plug. The protrusion is formed on the base in any known manner, such as by stamping or coining.
When the plug is inserted into the housing, the contact section of each resilient contact electrically engages with a corresponding constituent electrode of the plug to establish a desired electrical connection between the plug and the audio jack. At the same time, the protrusion of the retention pad bears against the plug with a predetermined force. Preferably, the protrusion of the retention pad exerts a strong enough force against the plug to keep the resilient contacts from being overloaded. Therefore, the amount of yield of the resilient contacts is greatly reduced. The height of the protrusion of the retention pad can be adjusted during its formation by, for example, precision stamping to meet the requisite criteria.